When I was a youth I used to make all kinds of pledges, and do my best to keep them, but I never could, because I didn't strike at the root of the habit - the desire; I generally broke down within the month.

Once I tried limiting a habit. That worked tolerably well for a while. I pledged myself to smoke but one cigar a day. But desire persecuted me every day and all day long; so, within the week I found myself hunting for larger cigars than I had been used to smoke; then larger ones still, and still larger ones.

Within the fortnight I was getting cigars made for me. They still grew and grew in size. Within the month my cigar had grown to such proportions that I could have used it as a crutch.